Enable Vertical Query Output in DuckDB

When using DuckDB’s command line interface (CLI), we can use the .mode command to change how query results are formatted. For example, we can output query results as a table, in CSV format, or even JSON. Another option is to output it in “line” mode, which outputs the query results vertically, as opposed to horizontally across the screen.

This article demonstrates how to enable vertical query output in the DuckDB CLI with line mode.

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How CONCAT_WS() Works in DuckDB

In DuckDB, the CONCAT_WS() function provides an efficient way to join strings with a specified separator. CONCAT_WS() stands for “concatenate with separator”, and many RDBMSs have such a function.

CONCAT_WS() is particularly useful when you need to combine multiple fields or values with a consistent delimiter.

Let’s explore its features and practical applications.

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An Overview of the CONCAT() Function in DuckDB

String concatenation is a common operation in database queries, and many database management systems (DBMSs) provide at least one or two ways to concatenate strings. DuckDB is no exception.

One option for concatenating strings in DuckDB is with the CONCAT() function. This function provides a robust and NULL-safe way to combine strings.

Unlike the concatenation operator (||), CONCAT() handles NULL values gracefully and provides a cleaner syntax for combining multiple strings.

In this article, we’ll explore everything from basic usage to advanced techniques and best practices.

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What ?TABLE? Means When using .help mode in DuckDB

If you’ve ever run .help mode in the DuckDB command line interface (CLI), you may have noticed that it returns information about the .mode command, including its syntax.

You might’ve noticed that there’s a ?TABLE? part in the syntax. What’s this about? Maybe you’ve tried it out and found that it didn’t appear to do anything?

In this article, I’ll explain what the ?TABLE? part is for, and I’ll run an example to demonstrate.

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